Digital signal recording method and apparatus and recording medium therefor

ABSTRACT

Digital signals are recorded in sequential tracks on a tape-form recording medium. In the case where the digital signals are recorded in accordance with a first recording format, at least first digital signals for normal reproduction are recorded in a single area of the first format on each track. In the case where the digital signals are recorded in accordance with at least a second recording format, at least the first digital signals are recorded in a specific area among divided areas of the second format, the divided areas being rewritable independently on each track, the specific area being common for both the first and second formats. And, second digital signals for special reproduction are recorded in previously determined areas among recording areas on each track, the recording areas being common for both the first and second formats.

BACKGROUND OF THE INVENTION

The present invention relates to a digital signal recording method andrecording apparatus and a recording medium therefor. More specificallythis invention relates to a digital signal recording method andapparatus for recording a plurality of different sorts of normalreproduction digital signals and special reproduction digital signals ona tape-form recording medium by use of a rotary head, and a recordingmedium used for the digital signal recording method and apparatus.

In general, digital signals are recorded in unit of data block on andreproduced from a tape-form recording medium, such as a magnetic tape byuse of a rotary head. There is a case that a trick play reproduction(special reproduction) such that digital signals are reproduced at aspeed different from the speed at which the digital signals arerecorded. The data recorded for the normal reproduction are reproduceddiscontinuously at certain time intervals in this case. The scanningpattern of the rotary head on the tape-form recording medium isdifferent from that obtained when the digital signals are reproduced inthe normal reproduction. It is thus difficult to obtain the trick playreproduction signals without any additional processing.

Therefore, conventionally, there has been known a digital signalrecording method for enabling the special reproduction as disclosed inJapanese Patent-Laid Open No. 1994-261278. This teaches that digitalsignals for the special reproduction are arranged and recorded on trackson which normal reproduction digital signals are recorded along therotary head scanning pattern obtained in the special reproduction.

In such a digital signal recording method, the recording format of thedigital signals recorded on each track of a tape-form recording mediumis kept constant. It is thus impossible to record digital signals ofdesired systems in various formats (e.g., such a format that a pluralityof data areas are arranged on a single track so that digital signals canbe recorded and reproduced independently) by use of a signal apparatus.

In addition, there is a case where the digital signals for the normalreproduction and the special reproduction are recorded on the recordingmedium under mixed conditions. The data rate of the special reproductiondigital signals and the arrangement positions of the specialreproduction digital signals in this case are different from each other.Because the recording formats of the digital signals are different fromeach other. There arises a problem in that a circuit for forming thespecial reproduction digital signals and a circuit for recording thespecial reproduction digital signals at specific positions on thetape-form recording medium are both complicated in circuit construction.

SUMMARY OF THE INVENTION

With these problems in mind, therefore, it is an object of the presentinvention to provide a digital signal recording method and apparatus anda recording medium used therefor, by which the normal reproductiondigital signals and the special reproduction digital signals can berecorded in accordance with mutually different formats under mixedconditions.

Further, another object of the present invention is to provide a digitalsignal recording method and apparatus and a recording medium usedtherefor, by which when the normal reproduction digital signals and thespecial reproduction digital signals are recorded on a recording mediumunder mixed conditions, the circuits for forming and recording thespecial reproduction digital signals can be simplified in circuitconstruction, in spite of the fact that the recording track formatsystems are different from each other.

To achieve the above-mentioned object, the present invention provides amethod for recording digital signals in sequential tracks on a tape-formrecording medium, comprising the steps of: in the case where the digitalsignals are recorded in accordance with a first recording format,recording at least first digital signals for normal reproduction in asingle area of the first format on each track; in the case where thedigital signals are recorded in accordance with at least a secondrecording format, recording at least the first digital signals in aspecific area among a plurality of divided areas of the second format,the divided areas being rewritable independently on each track, thespecific area being common for both the first and second formats; andrecording second digital signals for special reproduction in previouslydetermined areas among recording areas on each track, the recordingareas being common for both the first and second formats.

The method may further comprise the steps of: selecting either the firstor the second digital signals according to a data rate of the firstdigital signals; and recording the selected digital signals in thepreviously determined areas.

The method may further comprise the steps of: detecting the data rate ofthe first digital signals; and selecting the first digital signals whenthe detected data rate becomes higher than a predetermined data rate.

Further, the present invention provides an apparatus for recordingdigital signals in sequential tracks on a tape-form recording medium,comprising: first selecting means for selecting either first digitalsignals for normal reproduction or second digital signals for specialreproduction according to a data rate of the first digital signals;adding means, in the case where the digital signals are recorded inaccordance with at least a first recording format, for adding a headerindicating at least previously determined areas among recording areas oneach track to a data block of the selected digital signals and toauxiliary data to be recorded on an area other than a plurality ofdivided areas of the first format, the recording areas being common forthe first recording format and a second recording format, the dividedareas being rewritable independently on each track; second selectingmeans for selecting the digital signals without the header when thedigital signals are recorded in accordance with the second format,whereas selecting the digital signals with the header or the auxiliarydata with the header when the digital signals are recorded in accordancewith the first format; and recording means, in the case where thedigital signals are recorded in accordance with the second format, forrecording at least the first digital signals selected by the secondselecting means in a single area of the second format on each track, inthe case where the digital signals are recorded in accordance with thefirst format, for recording at least the first digital signals selectedby the second selecting means in a specific area among the divided areasof the first format, and for recording the second digital signalsselected by the second selecting means in the previously determinedareas.

The apparatus may further include detecting means for detecting the datarate of the first digital signals and applying a control signal to thefirst selecting means when the data rate becomes higher than apredetermined data rate, the first selecting means selecting the firstdigital signals in response to the control signal.

Further, the present invention provides a method for reproducing digitalsignals recorded in sequential tracks on a tape-form recording medium,comprising the steps of: reading the digital signals recorded in thesequential tracks on the recording medium; detecting address informationincluded in the read digital signals; reproducing first digital signalsfor normal reproduction and second digital signals for specialreproduction, and auxiliary digital signals on the basis of thedetecting address information, each second digital signal having afirst, a second, and a third data block aligned in this order, the firstand third data blocks storing the same data; selectively outputting thefirst digital signals or either the first or the second data block ofthe second digital signals in response to a control signal; andoutputting the auxiliary digital signals in response to another controlsignal.

Further, the present invention provides a tape-form recording medium onwhich digital signals are recorded in sequential tracks on the recordingmedium, comprising: a single area on each track for recording at leastfirst digital signals for normal reproduction in accordance with a firstrecording format; a plurality of divided areas rewritable independentlyon each track, for recording at least the first digital signals in aspecific area among the divided areas in accordance with a secondrecording format, the specific area being common for both the first andsecond formats; and a plurality of recording areas on each track forselectively recording the first digital signals and second digitalsignals for special reproduction accordance with a data rate of thefirst digital signals, the recording areas being common for both thefirst and second formats.

In the recording medium, it is preferable that the number of total datablocks recorded in the single area of the first format is equal to a sumtotal of the number of total data blocks recorded in the dividedindependently rewritable areas of the second format and the number ofdata blocks of the areas to be rewritten.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an embodiment of the digital signalrecording method and apparatus according to the present invention;

FIG. 2 is an illustration showing an example of data block format formedby the method according to the present invention;

FIG. 3 is an illustration showing an example of a first-system trackformat formed by the method according to the present invention;

FIG. 4 is an illustration showing an example of a second-system trackformed by the method according to the present invention;

FIG. 5 is an illustration showing a track format of an embodiment of therecording medium according to the present invention; and

FIG. 6 is a block diagram showing an embodiment of the digital signalreproducing apparatus according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described hereinbelowwith reference to the attached drawings.

FIG. 1 is a block diagram showing a recording apparatus for assistancein explaining the digital signal recording method and apparatusaccording to the present invention. In FIG. 1, digital signals forfirst-system normal reproduction (referred to as the normal reproductiondata, hereinafter) to be recorded in a first track format are inputtedthrough an input terminal 1. Second-system normal reproduction data tobe recorded in a second track format are inputted through an inputterminal 2a. Further, auxiliary data (AUX) to be recorded and reproducedin the second format separately from the second-system normalreproduction data are inputted through an input terminal 2b. Theseauxiliary data (AUX) are audio signals or other.

Here, in the present embodiment, the digital signals are recorded ontracks formed by a helical scanning type magnetic recording andreproducing apparatus (VTR). In this VTR, digital signals are recordedand reproduced on and from a magnetic tape wound obliquely around anouter circumferential side surface of a rotary body over about an180-degree angular range thereof. Further, the recording andreproduction are done while the magnetic tape is running at a constantspeed, by use of two opposing rotary heads attached to the rotary body180 degrees away from each other and having two different azimuthangles. Each track is constructed by arranging a plurality of data areasof a constant data rate (referred to as sync blocks) corresponding tothe afore-mentioned data blocks in accordance with the scanningoperation of the rotary head.

FIG. 2 shows an example of the format of a sync block. As shown, onesync block (i.e., a data block) is a 112-byte area formed bysynthesizing, in time series manner, a two-byte synchronizing signal(Sync) area 21 for reproducing the sync block, a three-byte address (ID)area 22, a three-byte header storing area 23 for storing various data, a96-byte data storing area 24, and an eight-byte parity area 25 forcorrecting any error of the sync block data.

In this embodiment, for instance, digital signals of a transport packet(TP) transmission system of MPEG2 (Moving Picture Expert Group 2) arerecorded in the above-mentioned data storing area 24, as the normalreproduction data or special reproduction data. Further, a single trackis formed by synthesizing a plurality of the sync blocks in time seriesmanner.

With respect to the track format, in the case of the first systemdigital signal recording, a first track format as shown in FIG. 3 isformed. Further, in the case of the second system digital signalrecording or the auxiliary signal recording, a second track format asshown in FIG. 4 is formed.

The first track format as shown in FIG. 3 is composed of a margin area31, a pre-amble area 32, a subsidiary code area 33, a post-amble area34, an IBG (interblock gap) area 35, a pre-amble area 36, a data area37, an error correction code area 38, a post-amble area 39, and a marginarea 40. Here, the data area 37 and the error correction code area 38constitute a major data area. This data area 37 is composed of 306 syncblocks, in which the first system digital signals (the normalreproduction data or the special reproduction data) DATA1 of 306 syncblocks are recorded. Further, the error correction code area 38 iscomposed of 30 sync blocks, in which external codes (C3 codes) forcorrecting errors of the first system digital signals DATA1 arerecorded.

Next, the second track format shown in FIG. 4 is used for the secondsystem digital signals and auxiliary signals, in which the samereference numerals have been retained for the same composing areas shownin FIG. 3. The second track format as shown in FIG. 4 is composed of amargin area 31, a pre-amble area 32, a subsidiary code area 33, apost-amble area 34, an IBG area 35, a pre-amble area 36, a first dataarea 41, a post-amble area 42, an IBG area 43, a pre-amble area 44, asecond data area 45, an error correction code area 46, a post-amble area39, and a margin area 40.

Here, the first data area 41, the post-amble area 42, the IBG area 43,the pre-amble area 44, and the second data area 45 are constructed by306 sync blocks which is the same as the data area 37 shown in FIG. 3.In the 306 sync blocks, the first data area 41 is composed of 23 syncblocks, in which the auxiliary signals AUX are recorded. Further, thepost-amble area 42, the IBG area 43, and the pre-amble area 44 arecomposed of two sync blocks, three sync blocks, and one sync block,respectively, so as to construct a rewritable edition gap area of sixsync blocks as a whole.

Further, in the second data area 45, the second system digital signals(the normal reproduction data or the special reproduction data) DATA2 of277 sync blocks are recorded. Further, in the error correction code area46, external codes (C3 codes) for correcting errors of the second systemdigital signals DATA2 are recorded. In more detail, error correctioncodes of 30 sync blocks formed for the data of 306 sync blocks in total(an addition of the 277 sync block DATA2 and the 29 sync block "0" data)are recorded in this error correction code area 46.

Returning to FIG. 1 again, when the first system normal reproductiondata are inputted through the input terminal 1, the inputted data arewritten in an input buffer memory 3, and further applied to a systemdetecting circuit 4 and a data rate calculating circuit 5. The systemdetecting circuit 4 detects the system of the inputted data. The datarate calculating circuit 5 calculates the data rate of the first systemnormal reproduction data. Further, when the second system normalreproduction data and the auxiliary signals are inputted through theinput terminals 2a and 2b, respectively, the inputted data and theauxiliary signals are written in the input buffer memory 3, and furtherapplied to the system detecting circuit 4. The second system normalreproduction data is also applied to the data rate calculating circuit5.

In accordance with the detected system, the system detecting circuit 4applies one-bit detection signal to a control circuit 6. In response tothe one-bit detection signal, the control circuit 6 forms and outputsvarious signals such as a read control signal applied to the inputbuffer memory 3, a select signal applied to a selecting circuit 9,header data, a synchronizing signal, address data, etc. all applied to aselecting circuit 9.

The data rate detecting circuit 5 calculates the data rate of theinputted normal reproduction data, and compares the calculated data ratewith a plurality of previously determined reference values to detect aset data rate range to which the inputted normal reproduction databelongs. The data rate detecting circuit 5 then outputs a select signalaccording to the detected data rate to the selecting circuit 9.

After having been stored in the input buffer memory 3, the first orsecond system normal reproduction data are read in response to the readcontrol signal applied by the control circuit 6 and then supplied to atrick play data forming circuit 7 and the selecting circuit 9. Further,when the auxiliary signals are stored in the input buffer memory 3, theauxiliary signals are supplied to a header adding circuit 10.

On the basis of the inputted normal reproduction data, the trick playdata forming circuit 7 forms of six sorts of trick playing (specialreproduction) data, and multiplexes four-byte additional data (e.g,packet arrival time and other data) with the formed trick playing dataas an additional header, respectively. The trick play data formingcircuit 7 then outputs the six sorts of data in parallel to write thesedata in six dedicated buffer memories 8 (TP1B to TP6B), respectively.

More in detail, the trick play data forming circuit 7 decodes theinputted normal reproduction data (MPEG transport stream), takes awaysome frames of the inputted data in accordance with trick playreproduction speeds, and encodes the data. Instead of that, the trickplay data forming circuit 7 may take out packets including independentlyreproducible blocks in accordance with trick play reproduction speeds.Further, the trick play data forming circuit 7 is not required when dataof normal reproduction data and previously formed trick play data beingtime-division multiplexed with each other via input terminal 1 aredistributed to the input buffer memory 3 and buffer memories 8,respectively.

The construction of the same sorts of the special reproduction data isthe same in both the cases where the first and second system digitalsignals are recorded.

The respective data stored in the six buffer memories 8 (TP1B to TP6B)are read on the basis of the read signal applied by the control circuit6, and then inputted to the selecting circuit 9. The selecting circuit 9selects any of the normal reproduction data and the six sorts of thespecial reproduction data TP1 to TP6 on the basis of both select signalsapplied by the control circuit 6 and the data rate calculating circuit5. The selecting circuit 9 then supplies the selected data to the headeradding circuit 10.

In other words, the selecting circuit 9 selects and outputs any of thenormal reproduction data and the six sorts of the special reproductiondata TP1 to TP6 in a previously determined specific sequence. Further,when any of the six sorts of the special reproduction digital signalsare outputted, any of the special reproduction data and the normalreproduction data are selected and outputted according to the data rateof the normal reproduction data detected by the data rate calculatingcircuit 5. In this case, as the data rate of the normal reproductiondata increases, the normal reproduction data are selected, instead ofthe special reproduction data (e.g., TP1 to TP6) of a lower priority.

Further, when the special reproduction data TP2 to TP6 are selected andoutputted, as described later in further detail, the selecting circuit 9selects those data in such a way that: a plurality of data blocks of thespecial reproduction data recorded under overlapped conditions arearranged in both front and rear of a plurality of data blocks of thespecial reproduction data recorded once without being overlapped.

The normal reproduction data and the special reproduction data TP1 toTP6 or time-series synthesized data formed of parts of these data alloutputted by the selecting circuit 9 are supplied to the header addingcircuit 10. The header adding circuit 10 adds three-byte header dataapplied by the control circuit 6 to the head of these data. The headerdata are stored in the header storing area 23 shown in FIG. 2. In thisembodiment, the header data includes at least map data and adiscriminate data. The map data indicates a track pattern (e.g., asshown in FIG. 5) in which the six-sorts of special reproduction data TP1to TP6 are arranged and recorded on a specific area previouslydetermined on the tape-form recording medium 18. The discriminate datadiscriminates which one of the special reproducing data TP1 to TP6 andthe normal reproduction data are selected and recorded on the six-sortsof special reproduction data (TP1 to TP6) recording areas, respectively.

The 99-byte digital signals composed of the header and the normalreproduction data or the special reproduction data both read by theheader adding circuit 10 are supplied to an external code formingcircuit 11. This external code forming circuit 11 forms 30 sync blockexternal codes as the error correcting codes for the sync block datarecorded on one-track data area. The sync block data are 306 sync blockdata stored in the data area 37 shown in FIG. 3 in the case of the firstsystem. Or, the sync block data are 277 sync block data stored in thedata area 45 shown in FIG. 4 in the case of the second system.

In the second system, the external code forming circuit 11 forms anexternal code for 306 (in total) sync block data obtained by adding the277 sync block input digital signals and 29 sync block "0" datacorresponding to 29 sync blocks of the data area 41, the post-amble area42, the IBG area 43, and the pre-amble area 44 shown in FIG. 4. Theexternal code is stored in the error correcting code area 38 shown inFIG. 3 in the case of the first system digital signals. Or, the externalcode is stored in the error correcting code area 46 shown in FIG. 4 inthe case of the second system digital signals.

The digital signals composed of the header, the digital data and theexternal codes formed by the external code forming circuit 11 aresupplied to an internal code forming circuit 13. The internal codeforming circuit 13 forms an eight-byte parity as an internal code inunit of 99 bytes. Further, the header and the auxiliary data (AUX) readby the header adding circuit 10 are inputted to another external codeforming circuit 12. The external code forming circuit 12 forms 5 syncblock external codes for each 18 sync blocks. The auxiliary data of 23sync blocks are supplied to another internal code forming circuit 14, toform an eight-byte parity as an internal code in unit of 99 bytes.

The digital signals of data, a header, external codes, and internalcodes formed by the internal code forming circuits 13 and 14 aresupplied to an adder circuit 15. The adder circuit 15 forms sync blocksby adding the two-byte synchronizing signal as shown by Sync and thethree-byte address data as shown by ID both in FIG. 2 to the supplieddigital signals. After that, the digital signals are supplied to anotherselecting circuit 16 in unit of sync blocks. When the first systemnormal reproduction data are inputted through the input terminal 1, inresponse to the select signal applied by the control circuit 6, theselecting circuit 16 selects the sync blocks including the first systemnormal reproduction data or the special reproduction data. These are thedata inputted through the internal code forming circuit 13 and the addercircuit 15, respectively. On the other hand, when the second systemnormal reproduction data and the auxiliary data (AUX) are inputtedthrough the input terminals 2a and 2b, respectively, in response to theselect signal applied by the control circuit 6, the selecting circuit 16selects the sync blocks including the second system normal reproductiondata or the special reproduction data or the auxiliary data (AUX). Theseare the data inputted through the internal code forming circuit 13 and14 and the adder circuit 15, respectively.

The output signals of the selecting circuit 16 are multiplexed with apre-amble signal, a subsidiary code signal, a post-amble signal, etc.,to be recorded in the areas 32, 33, 34, 39, 42, 44, etc. shown in FIGS.3 and 4. The multiplexed data are then modulated and amplified by asignal recording circuit 17. Further, the modulated and amplifiedsignals are recorded on the recording medium 18 (a magnetic tape, inthis embodiment) by a recording mechanism using a well-known rotary head(not shown). As described above, the normal reproduction data and thespecial reproduction data TP1 to TP6 can be recorded by forming thetrack pattern as shown in FIG. 5. Further, the normal reproduction dataare recorded, instead of a part or all of the special reproduction dataTP1 to TP6, according to the data rate of the normal reproduction data.

Further, in the case where the second system digital signals arerecorded, only one of the second system normal reproduction datainputted through the input terminal 2a and the auxiliary data (AUX)inputted through the input terminal 2b can be recorded independently.

The track pattern of an embodiment of the recording medium according tothe present invention will be described hereinbelow with reference toFIG. 5. FIG. 5 shows 24 pairs of tracks (i.e., 48 tracks) recorded by afirst rotary head having a positive azimuth angle and a second rotaryhead having a negative azimuth angle. Further, each track shows the 336sync blocks composed of the 306 sync block data area 37 and the 30 syncblock error correcting code area 38 both shown in FIG. 3. Or, each trackshows the 336 sync blocks composed of the data areas from the first dataarea 41 to the error correcting code area 46 shown in FIG. 4.

As understood by FIG. 5, the special reproduction data TP1 to TP6 arearranged and recorded at previously determined specific positions. Therecording ranges are set to the second data area 45 of 277 sync blocks(excluding the first data area 41 of 23 sync blocks and the editing gapof six sync blocks composed of the areas 42 to 44). Also in the case ofrecording the first system digital signals, the special reproductiondata TP1 to TP6 are recorded at a part of the 277 sync block rangeexcluding the 29 head sync blocks from the data area 37 of 306 syncblocks shown in FIG. 3.

In this embodiment shown in FIG. 5, various data are recorded atpreviously determined specific positions, respectively. These variousdata are the first special reproduction data TP1 of four-time (4×) speedin the forward direction, the second special reproduction data TP2 of12-time (12×) speed in the forward direction, the third specialreproduction data TP3 of 24-time (24×) speed in the forward direction,the fourth special reproduction data TP4 of four-time (-4×) speed in thereverse direction, the fifth special reproduction data TP5 of 12-time(-12×) speed in the reverse direction, and the six special reproductiondata TP4 of 24-time (-24×) speed in the reverse direction.

Here, the first special reproduction data TP1 are composed of 45 syncblocks; the second special reproduction data TP2 are composed of 46 syncblocks; the third special reproduction data TP3 are composed of 14 syncblocks; the fourth special reproduction data TP4 are composed of 58 syncblocks; the fifth special reproduction data TP5 are composed of 23 syncblocks; and the six special reproduction data TP6 are composed of 13sync blocks, respectively. The block lengths of these specialreproduction data are set in such a way that the data can be reproducedeven if the rotary head scanning is slightly shifted from thepredetermined pattern in the trick playing operation.

Further, in FIG. 5, the portions where the special reproduction data TP1to TP6 are not recorded indicate the track portions where the normalreproduction data are recorded. In addition, two white portions betweenwhich each special reproduction data TP2 to TP6 is sandwiched are syncblocks where the same data are recorded.

Table 1 lists the number of sync blocks, the recording data rate, thereproducing data rate, etc. of the respective special reproduction dataon the track pattern shown in FIG. 5. In Table 1, SB is an abbreviationof sync block, and the number of sync blocks are calculated on thecondition that one SB is 94 bytes on an average.

                  TABLE 1                                                         ______________________________________                                             B U-    S-      S-                 REC   REP                             SP   RST/S   B(a)/   B(b)/                                                                              REC    REP    D-RT  D-RT                            R    CN      SCN     SCN  SB/TPF SB/SCN kbps  kbps                            ______________________________________                                         +4  2       45       0    90    90     507.6 2.03                            +12  3       14      16   138    90     259.44                                                                              2.03                            +24  9        6       4   126    90     118.44                                                                              2.03                             -4  2       32      13   116    90     654.24                                                                              2.03                            -12  5       13       5   115    90     216.2 2.03                            -24  9        7       3   117    90     109.98                                                                              2.03                            ______________________________________                                    

(SP R: a speed ratio; SCN: scanning; REC: recording;

REP: reproduction; and D-RT: data rate)

Further, SB(a) denotes the number of sync blocks in which data isrecorded once in the special reproduction data blocks; SB(b) denotes thenumber of sync blocks in which the same data are recorded twice in thespecial reproduction data blocks; and TPF implies trick play frame; andSCN implies one revolution of a rotary body (e.g., a rotary drum).

When all the six sorts of special reproduction data TP1 to TP6 arerecorded as shown in FIG. 5 in accordance with Table 1, the ratio of allthe special reproduction data rate to all the recorded data rate (60×306(SB/s)) is 13.5%. This is because all the special reproduction data arerecorded at a speed of 2481.25 SB per second. In this case, therecordable data rate of the normal reproduction data is 11.9 Mbps.

The embodiment is described under the condition that the data rate ofthe normal reproduction data is changed. And, the recorded data rate ofthe special reproduction data is reduced when the data rate of thenormal reproduction data becomes higher than 11.9 Mbs. In this case,during reproduction, the special reproduction data TP1 to TP6 arereduced beginning from the lower priority order in sequence.

In the embodiment, the priority order of the 24-time speed specialreproduction data TP3 and TP6 is the lowest priority. Further thepriority increases in the order of the reverse-direction four-time speedspecial reproduction data TP4, the forward-direction four-time specialreproduction data TP1, the reverse-direction 12-time speed specialreproduction data TP5, the forward-direction 12-time specialreproduction data TP2. Then, as the data rate of the normal reproductiondata increases beyond 11.9 Mbps, the special reproduction data recordingis omitted in the order of (1)TP3 and TP6, (2)TP4, (3)TP1, (4)TP5,(5)TP2. Further, finally, all the special reproduction data recordingsare omitted, and only the normal reproduction data are recorded.

Table 2 lists the recorded special reproduction data, the proportionoccupied by the special reproduction data, and the data rate of therecordable normal reproduction data.

                  TABLE 2                                                         ______________________________________                                                       RATIO OCCUPIED                                                                              RECORDABLE                                                      BY SPL DATA   NOR DATA                                         RECORDED SPL DATA                                                                            (%)           RATE (Mbps)                                      ______________________________________                                        NONE           0             13.8                                             TP2            1.9           13.5                                             TP2, TP5       3.4           13.3                                             TP2, TP5, TP1  7.1           12.8                                             TP2, TP5, TP1, TP4                                                                           11.9          12.2                                             TP2, TP5, TP1, TP4, TP3,                                                                     13.5          11.9                                             TP6                                                                           ______________________________________                                    

In the above Table 2, the recordable and reproducible normalreproduction data rate is the data rate of the first-system normalreproduction data recorded by the first format. Therefore, thesecond-system normal reproduction data recorded by the second formatbecomes smaller than these listed values by about 1.31 Mbps (=(23+6)SB/track ×60 track/s ×94 byte/SB ×8 bit/byte).

In the present embodiment, in both the cases where the first-systemdigital signals and the second-system digital systems are recorded, thedata rate required for the special reproduction data TP1 to TP6 is thesame as far as the same sort of the special reproduction data arerecorded. It is thus possible to use the trick play data forming circuit7 for forming the special reproduction data in common for both the firstand second system digital signals. This results in the forming circuitbeing simplified to that extent.

Further, in the present embodiment, in both the cases where thefirst-system digital signals and the second-system digital signals arerecorded, the recording positions where the special reproduction dataTP1 to TP6 are recorded are fixedly determined as shown in FIG. 5. It isthus possible to simplify the function required for the circuit forarranging and recording the special reproduction data TP1 to TP6 on thetrack to that extent.

Now, the construction and operation of the digital signal reproducingapparatus for reproducing the recording medium according to the presentinvention will be described hereinbelow with reference to FIG. 6.

A recording medium 51 is the same as the recording medium 18 shown inFIG. 1, which is formed with a track pattern as shown in FIG. 5. Afterhaving been reproduced by use of a well-known reproducing mechanism(including the rotary head), the reproduced digital signals areamplified and demodulated by a signal reproducing circuit 52. And thenthe demodulated signals are applied to an ID detecting circuit 53 todetect the address data (ID). On the basis of the ID detected by the IDdetecting circuit 53, the digital signals stored in the data area 37 andthe error correction code area 38 shown in FIG. 3 are supplied to anerror correcting circuit 54. Further, On the basis of the ID, thedigital signals stored in the data area 45 and the error correction codearea 46 shown in FIG. 4 are also supplied to the error correctingcircuit 54. On the other hand, the reproduced digital data (AUX) storedin the data area 41 shown in FIG. 4 are supplied to another errorcorrecting circuit 55.

The reproduced digital signals error-corrected by the error correctingcircuit 54 are supplied to a control circuit 56 and further to a datadistributing circuit 57. Further, the reproduced digital signalserror-corrected by the error correcting circuit 55 are supplied to anAUX buffer memory 58.

The control circuit 56 analyzes the header of the reproduced digitalsignals and outputs a control signal to the data distributing circuit57. Further, the control circuit 56 generates write control signals WTP1to WTP6, WN and WA applied to buffer memories 59-1 to 59-6, a normalbuffer memory 60 and an AUX buffer memory 58, respectively. In addition,the control circuit 56 analyzes the four-byte additional data(additional header) of the reproduced digital signals to detect the dataarrival time, and generates read-out control signals RTP1 to RTP6 and RNand RA, so that all the data can be read at the same timing.

On the basis of the control signals, when the inputted reproduceddigital signals are of the special reproduction data TP1 to TP6, thedata distributing circuit 57 distributes the reproduced digital signalsto each of the dedicated buffer memory 59-1 to 59-6. Further, when theinputted reproduced digital signals are of the normal reproduction data,the data distributing circuit 57 supplies the reproduced digital signalsto the normal buffer memory 60. In the case of the special reproductiondata TP2 to TP6, only one of the two places (the white portions in FIG.5) where the same data blocks of the special reproduction data arerecorded is selected and outputted. Therefore, even if the head scanningis slightly shifted away from the predetermined pattern, it is possibleto reproduce the special reproduction data under excellent conditions.

The special reproduction data TP1 to TP6 stored in the buffer memories59-1 to 59-6, respectively, and the normal reproduction data stored inthe buffer memory 60 are read on the basis of read control signals RTP1to RTP6 and RN. And the read signals are inputted to a selecting circuit61. The selecting circuit 61 selects one sort of data designated by thecontrol circuit 56 and outputs the selected data as the reproductiondata. On the other hand, when the auxiliary data (AUX) are reproduced,the control circuit 56 supplies a read control signal RA to the AUXbuffer memory 58 that outputs the reproduced auxiliary data.

Further, the present invention is not limited only to theabove-mentioned description. For instance, the present embodiment hasbeen explained by taking the case where digital signals are recorded andreproduced in accordance with any one of the two-system formats.However, the present invention can be applied to the case of three ormore system formats by recording the special reproduction data at a partof the area common for all the systems.

Further, in the above-mentioned embodiment, any one of the first systemand the second system is decided automatically by the system detectingcircuit 4. Without being limited only thereto, the system can be ofcourse decided manually. Further, in the above-mentioned embodiment, thespecial reproduction data are formed on the basis of the normalreproduction data. It is also possible to form and input the specialreproduction data separately from the normal reproduction data.

As described above, in the digital signal recording method and apparatusaccording to the present invention, the same area for recording thespecial reproduction digital signals are used in common for both thefirst and second format recordings. It is thus possible to use thecircuit for arranging and recording the special reproduction digitalsignals on the tracks in common for each format recording. This resultsin the simplified circuit construction.

Further, in the digital signal recording method and apparatus accordingto the present invention, the special reproduction digital signals arerecorded in the same construction in both the first and second formatrecordings. Further, the data rate of the special reproduction digitalsignals is equalized in both the first and second format recordings. Itis thus possible to use the circuit for forming the special digitalsignals in common for each format recording. This results in thesimplified circuit construction.

Further, in the digital signal recording method and apparatus accordingto the present invention, any of the special reproduction digitalsignals and the normal reproduction digital signals are selected andrecorded at the recording area for the special reproduction digitalsignals, according to the data rate of the normal reproduction digitalsignals. It is thus possible to eliminate the switching of the circuits(for addressing) for arranging the special reproduction digital signals.This results in the circuit function being reduced markedly.

Further, in the recording medium according to the present invention, thespecial reproduction digital signals (instead of the normal reproductiondigital signals) are recorded in a specific area previously determinedin the digital signal recording area used in common for both the firstand second formats on the respective tracks. It is thus possible toreproduce the special reproduction digital signals from the same area inany format reproduction by the reproducing apparatus.

We claim:
 1. An apparatus for recording digital signals in sequentialtracks on a tape-form recording medium, comprising:first selecting meansfor selecting either first digital signals for normal reproduction orsecond digital signals for special reproduction according to a data rateof the first digital signals; adding means, in the case where thedigital signals are recorded in accordance with at least a firstrecording format, for adding a header indicating at least previouslydetermined areas among recording areas on each track to a data block ofthe selected digital signals and to auxiliary data to be recorded on anarea other than a plurality of divided areas of the first format, therecording areas being common for the first recording format and a secondrecording format, the divided areas being rewritable independently oneach track; second selecting means for selecting the digital signalswithout the header when the digital signals are recorded in accordancewith the second format, whereas selecting the digital signals with theheader or the auxiliary data with the header when the digital signalsare recorded in accordance with the first format; and recording means,in the case where the digital signals are recorded in accordance withthe second format, for recording at least the first digital signalsselected by the second selecting means in a single area of the secondformat on each track, in the case where the digital signals are recordedin accordance with the first format, for recording at least the firstdigital signals selected by the second selecting means in a specificarea among the divided areas of the first format, and for recording thesecond digital signals selected by the second selecting means in thepreviously determined areas.
 2. The apparatus according to claim 1,further comprising detecting means for detecting the data rate of thefirst digital signals and applying a control signal to the firstselecting means when the data rate becomes higher than a predetermineddata rate, the first selecting means selecting the first digital signalsin response to the control signal.
 3. A method for reproducing digitalsignals recorded in accordance with a first or a second recording formatin sequential tracks on a tape-form recording medium, comprising thesteps of:reading the digital signals recorded in the sequential trackson the recording medium, the digital signals recorded on which areauxiliary digital signals, in the case where the digital signals havebeen recorded in accordance with the first recording format, firstdigital signals for normal reproduction and second digital signals forspecial reproduction in a first area on each track, and in the casewhere the digital signals have been recorded in accordance with thesecond recording format, the first and the second digital signals in asecond area that corresponds to a part of the first area on each track,the second digital signals for special reproduction having been recordedin the identical areas in the first and the second areas; detectingaddress information included in the read digital signals; reproducingthe first digital signals for normal reproduction and the second digitalsignals for special reproduction, and the auxiliary digital signals onthe basis of the detecting address information, each of said seconddigital signals having a first, a second, and a third data block alignedin this order, the first and third data blocks storing the same data;selectively outputting the first digital signals or either the first orthe second data block of the second digital signals in response to acontrol signal; and outputting the auxiliary digital signals in responseto another control signal.
 4. A method for recording digital signals insequential tracks on a tape-form recording medium, comprising:selectingeither first digital signals for normal reproduction or second digitalsignals for special reproduction according to a data rate of the firstdigital signals; adding, in the case where the digital signals arerecorded in accordance with at least a first recording format, a headerindicating at least previously determined areas among recording areas oneach track to a data block of the selected digital signals and toauxiliary data to be recorded on an area other than a plurality ofdivided areas of the first format, the recording areas being common forthe first recording format and a second recording format, the dividedareas being rewritable independently on each track; selecting thedigital signals without the header when the digital signals are recordedin accordance with the second format, otherwise selecting the digitalsignals with the header or the auxiliary data with the header when thedigital signals are recorded in accordance with the first format; andrecording, in the case where the digital signals are recorded inaccordance with the second format, at least the first digital signalsselected by the step of selecting the digital signals in a signal areaof the second format on each track, otherwise recording, in the casewhere the digital signals are recorded in accordance with the firstformat, at least the first digital signals selected by the step ofselecting the digital signals in a specific area among the divided areasof the first format, and recording the second digital signals selectedby the step of selecting the digital signals in the previouslydetermined areas.
 5. The method according to claim 4, further comprisingdetecting the data rate of the first digital signals, wherein the stepof selecting the first or second digital signals selects the firstdigital signals when the data rate becomes higher than a predetermineddata rate.